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Zhao C.,Wuhan University of Technology | Yang Y.,Earth Science and Resource Engineering | Wu Z.,Soochow University of China | Field M.,Monash University | And 3 more authors.
Journal of Materials Chemistry A | Year: 2014

Ordered mesoporous carbons, as potential catalyst supports, have attracted great attention in the catalysis field in recent years. Researchers have attempted to introduce guest particles into these carbons by versatile methods. Great success has been achieved with noble metal particles because of their lower sintering tendency. However, challenges occurred with more active metals such as cobalt because of their much higher sintering tendency, the hydrophobic nature of the carbon surface and channel confinement effects, which were believed to have prevented the wetness of the surface. Most researchers found that the carbon surface had to be specially treated to achieve good metal dispersion. In our current work, cobalt@carbon composites were synthesized using CMK-3 as the carbon support and cobalt nitrate hexahydrate as the metal precursor. We demonstrated the facile control of the metal particle size and dispersion by carefully controlling the impregnation conditions according to the physical chemistry of the precursor. Our results suggested that not only the acid pre-treatment of the carbon surface and the ammonia post-treatment of the cobalt nitrate precursor improved the metal dispersion but also simple impregnation itself could achieve good metal dispersion if the preparation conditions were controlled as suggested. Highly thermal stable cobalt@carbon composites with very well-controlled cobalt dispersion (15 wt%) and particle size (∼4-20 nm) were produced. © 2014 the Partner Organisations. Source


Zhao C.,Wuhan University of Technology | Yang Y.,Earth Science and Resource Engineering | Chen W.,Wuhan University of Technology | Webley P.A.,Monash University | And 3 more authors.
Advanced Materials Research | Year: 2011

Ordered high surface area microporous carbon molecular sieves containing well-dispersed platinum nanoparticles have been prepared by chemical vapor deposition method. Acetonitrile was employed as carbon and nitrogen precursors to yield N-doped carbon molecular sieves. N-doped carbons have an average nitrogen content of ∼ 4.1 wt%. Electrochemical tests showed that the rectangular-shaped CVs of N-doped carbons could be well retained over a wide range of scan rates (5∼100 mV/s), and the CV curves presented a steep current change at the switching potentials. N-doped carbons exhibited excellent performance as an electrochemical supercapacitor with a calculated specific capacitance of 168 F/g. Meanwhile, it was noticed that a reasonable Pt loading would help to improve the capacitance. It was proposed that the polarizability or surface state modification by nitrogen doping and regular interconnected porous structure might contribute to the improvement of N-doped carbons' electrochemical properties. © (2011) Trans Tech Publications, Switzerland. Source


Zhao C.,Wuhan University of Technology | Yang Y.,Earth Science and Resource Engineering | Chen W.,Wuhan University of Technology | Webley P.,Monash University | Cao J.,Wuhan University of Technology
Advanced Materials Research | Year: 2012

Aluminophosphate molecular sieves (AlPO4-5s) with fibrous morphology were readily prepared via hydrothermal method at 180 °C with the initial molar ratio of Al(O iPr) 3: H 3PO 4: TrPA: HF: H 2O as 1: 0.83: 1: 0.8: 70. The morphology and structure of the prepared AlPO 4-5s were characterized by XRD, SEM, TEM and nitrogen sorption measurement. The morphology development and structure evolution mechanism were proposed. © (2012) Trans Tech Publications, Switzerland. Source


Guo X.,Wuhan University | Guo X.,Petrochina | He S.,Wuhan University | Liu K.,Earth Science and Resource Engineering | And 3 more authors.
Journal of Petroleum Geology | Year: 2011

Condensates are present in the PY30-1 structure in the Panyu Uplift, Pearl River Mouth Basin. Biomarkers and compound-specific stable carbon isotope ratios of three condensate and two source rock samples indicate that the condensates were generated by lacustrine mudstones and coals in the Oligocene Enping Formation with a minor contribution from mudstones in the Eocene Wenchang Formation. Elevated vitrinite reflectance values, high smectite-illite transformation ratios, and elevated fluid inclusion homogenization temperatures (about 100®C higher than normal borehole temperatures) point to the influence of hydrothermal fluids at the PY30-1 structure. Hydrocarbon migration was found to have occurred at the same time as hydrothermal activity. Modelling of formation pressure evolution in the Wenchang and Enping Formation source rocks in the Baiyun Depression, adjacent to the south of the Panyu Uplift, suggest that there were three episodes of overpressure release at approximately 40-37 Ma, 33-31 Ma and 16-10 Ma. Overpressure release was probably induced by uplift and erosion during the Zhuqiong, Nanhai and Dongsha phases of tectonic deformation, respectively. The third episode of overpressure release coincided with the main phase of hydrocarbon migration. The accumulation of condensates at the PY30-1 structure probably followed hydrocarbon expulsion from source rocks as a result of overpressure release in the adjacent Baiyun Depression. Vertical migration into overlying reservoir rocks occurred through faults associated with a fluid diapir which is present at the core of the PY30-I structure. The faults are pathways along which petroleum can migrate up to shallow reservoirs. © 2011 The Authors. Journal of Petroleum Geology © 2011 Scientific Press Ltd. Source

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